# File lib/compass/sass_extensions/sprites/layout.rb, line 24
          def properties
            if @width.zero?
              raise Compass::SpriteException, "You must set the width fetching the properties"
            end
            if @height.zero?
              raise Compass::SpriteException, "You must set the height fetching the properties"
            end

            [@images, @width, @height]
          end